#[cfg(test)]
mod test_arithmetic {
    #[test]
    fn add() {
        let result = crate::add(2, 2);
        assert_eq!(result, 4);
    }
    #[test]
    fn minus() {
        let result: u16 = crate::minus(10, 5);
        assert_eq!(result, 5);
    }
}